Many mobile computing devices include computing processors that can download and execute applications. Some mobile computing devices include sensors that can take sensor measurements. Example sensors include a location sensor, an accelerometer, a gyroscope, a magnetometer, or the like. Some applications may monitor sensor measurements to determine context. For example, an application may monitor the location sensor to determine a location of the mobile computing device. An application may monitor the accelerometer to determine a number of steps that a user of the device may have traversed during a day. Some application developers spend vast amounts of time writing code, so that their applications can determine context.